(1) Field of the Invention
The present invention relates to a document reading apparatus capable of sequentially reading documents stacked on an automatic document feeder and a document set on a platen as well as relating to an image forming apparatus including this document reading apparatus. This document reading apparatus is suitably applied to a scanner device, copier, facsimile machine or a multi-functional machine having the functions of these in combination.
(2) Description of the Prior Art
The document reading apparatus provided for a scanner, copier, facsimile machine or the like has an automatic reading function of reading stacked documents one page at a time with an automatic document feeder (which will be referred to hereinbelow as “ADF”) and a flat bed scanner (which will be referred to hereinbelow as “FBS”) function of reading each document which is manually set and pressed on the platen.
The image reading apparatus disclosed in patent document 1 (Japanese Patent Application Laid-open 2005-165182), in order to prevent a document from being left behind after read when document reading is performed in the FBS mode, includes a device for detecting the document left and reminding the operator to take it back. Specifically, a document is set on the platen for the FBS mode and pressed thereon by closing a document pressing plate member, then the reading operation by a scanner is performed. A sensor is arranged near the hinge of the pressing plate member while sensors for detecting the document size are disposed at predetermined positions in the platen. Information from these sensors is transmitted to the controller so that the controller can output a warning when a forgotten document is detected based on the pressing plate opening and closing signal and the reading operation complete signal.
However, patent document 1 merely demonstrates that the apparatus described therein is configured to give warning when document reading is going to be performed through the ADF even though a document is left on the flat bed scanner. That is, there is no reference to reading of documents through the ADF when a document has been set on the flat bed scanner.
Further, in a case where OHP sheets, postcards or other special documents are wanted to be copied as one file (job) including other documents, the OHP sheets, postcards and other special documents are not allowed to be conveyed by the ADF, hence these special documents need to be copied by being set on the platen. Hence it was impossible to handle these special documents as one file with the documents that can be processed through the ADF. Therefore, when documents to be copied through the ADF and documents to be copied through the platen are mixed up together, the operator has to change the documents from those handled by the ADF to those read through the platen and vice versa. Moreover, when multiple sets of copies need be made on a copier with no mechanical sorter, it is still necessary to manually rearrange the resultant copies even if the order of copying the ADF documents and platen documents is adjusted.